This document contains very in-depth research on brain breaks. For me, it helped me put into perspective the outcomes expected for my entire school and how I could help achieve those goals via brain breaks.
I love these free brain break cards for use in my classroom. Just by picking them up my students get excited. My students are allowed to pick from the cards and it helps them become invested in the process.
No need to go searching for appropriate brain breaks. Here is a list of seven YouTube channels that have short brain breaks. My students especially love the Cosmic Kids Yoga and will request the longer versions for indoor recess.
If you are ever strapped for time, this 16-page read will do just the trick. It takes a look at high school level students and researches whether students who receive brain breaks perform differently from those who do not receive brain breaks.